What to know when looking to buy a diamond

When looking to purchase a diamond, there are a few things to consider, most importantly; cut, colour & clarity. It is vital that any diamond's certificate declares that the dimensions are "very good" or "excellent". If a diamond is polished too deep or too shallow, the light entering the diamond will not reflect back through the top, causing it to appear dull and to lose brilliance (as indicated in the following diagrams).